Metal-pickling process



METAL PICKLING PROCESS Filed April 4. 1923 WQTYM A TTOR/VfVS.

Patented June 30, 1925.

UNITED STATES 1,544,506 PATENT orrics.

JOHN B. TYTUS, OF MIDDLETOWN, OHIO, ASSIONOR TO THE AMERICAN ROLLING MILL COMPANY, OF MIDDLETOVVN, OHIO. A CORPORATION OF OHIO.

METAL-PICKLING PROCESS.

Application filedApril 4, 1923. Serial No. 629,764.

10 ing, forming part of this specification.

My invention relates to a process of pick ling metal, particularly sheet metal, which is continuous, and uses simple apparatus which is easy to operate.

In one aspect my invention bears a resemblance to strip of wire pickling processes, in which, in order to maintain a continuous movement of the metal, arrangements are made to secure the end of each strip or strand to the beginning of the next one.

In ferrous metal practice, however, strips are much longer than sheets of metal, and are wound on drums so as to form a roll. The feed of the strips through a pickling 25 bath is usually accomplished by winding them off of supply drums onto receiving drums, with idler rolls, used to enforce a movement through the pickling bath; Due to the area to be pickled strip and wire require a much shorter exposure to acid action. Sheet steel or iron comes in much shorter pieces than strip and usually is distinguished from strip steel by its width, also. In this specification, however, I do not wish to draw my process would serve for wide strips, as well as sheets. It would also serve for narrow strips, although such metal would probably be handled better by winding drums.

It is the object of my invention to provide a process of pickling wherein a number of sheets of metal, stitched or welded together lengthwise may be fed through a pickling bath, wherein the inet-al is fully exposed to pickle liquor onall sides, wherein the feed is simple and adequate for wide metal sheets, and wherein provision is made for sufficient agitation and acid contact to fully pickle sheets-in a short time; and in a limited space. By limited space, I mean that the .method is devised so that the length of apparatus is not great.

It will be understood that continuous pickling of sheets, by feeding them along between pinch rolls in an acid bath, or on some any definite line between strips and sheets, .as

rectilinear (-oln'eyel through the bath, requires structure of great length so that sutlicient acid exposure can be gained and enough sheets can he in the bath at the same time to provide for production speed that tallies with the sheet annealing processes.

Among other points of my process it should be noted that it does not require the submersion of the sheet feeding devices in the pickle liquor.

It is also my object to provide for a counterflow of pickle liquor, in a continuous pickling process. 1

These objects I accomplish by that certain process to be hereinafter more specifically pointed out and the novelty therein duly claimed.

In the drawings:

Figure l is a plan view showing a seriesof sheets secured together by welding.

Figure 2 is a more or, less diagrammatic side elevation showing. the operation of my process.

I have shown several sheets of metal 1, in which the ends of the sheets have been trimmed so as to leave suflicient metal for a welded butt or lap joint. Thus the sheets have ends 2 and 3, which are later to be cut away along the lines 4 and 5. leaving sheets of full length at the end of the process.

In rolling sheets there are always atboth ends thereof, uneven curved portions, which have to be removed, and in rolling, suflicient metal is provided so that these ends may be removed, leaving a sheet of the length desired.

In my process the sides of the sheets are trimmed, and the ends are trimmed enough to leave the portions 2 and 3, as abovenoted, which ends are lap welded together at 6, or stitched together or butt welded, as may be found desirable.

Then when the process of pickling is over,

from left to right of Figure 2, and the pickle iquor is moved through the. various compartments in the opposite direction.

Thus as indicating a method of counterflow for the pickle liquor, I show inflow pipes 10, 11, and 12, each lower than the other, the pipes 11 and 12 taking out of the bottom of the compartments from which they run. By pumping pickle liquor into pipe 10, and letting it flow out of pipe 14, at the same rate, I obtain a flow into the top of the last compartment, out of the bottom of this compartment into the next one ahead, and so on, in each instance draining out of the bottom. 7

I have shown one double compartment and two singles, and it will beunderstood that the size of the compartments will be as preferred.- I prefer to have each compartment a-double one for the pickling of ingot iron material in sheet form. The tank may be of separate vessels, instead of one'vessel with partitions, as will be obvious.

Located on the top of the tank are a series of driven drums 15, same being arranged so that the strip of sheets may hang in a loop 16 between each druml The strip of sheets enters over the first drum, then loops down into the first compartment, and up over the second drum and so on. c The removable idler drums 17, which may engage one or both adjacent drums 15, are shown inFigure 2, but I do not find them at all essential. I have found that the driving of the drums 15 will feed the metal along, and that the strip of sheets is heavy enough so that it will hangdown to the base of the tank, but will not accumulate there, since if or when theloop strikes the bottom of the tank, the stiffness of the piece will be sufficient to cause the drum that has fed it into the loop, to slip around under it, andthus stop feeding until the following drum has taken-up the slack. The idlers may be used to gain a positive drive or they may be in a loose engagement with the strip being fed, or may be entirely omitted.

The friction of the strip of sheets on the drums will provide a suitable dra that sets up a proper feed, and in practice the loops hang evenly and feed steadily, without the'idlers.

The speed of travel will be suflicient to take care of a strip of sheets that is passing through aheat treating furnace and from thence to the pickler,

As each section of the strip of sheets feeds down'through the pickle liquor and thence up and around a drumanddown again througha. series of loops, there isset up a proper agitation and washing action throughout the entire strip. The acid ac-- tion is thus more fully operative than in the dipping method where packs of sheets are raised and lowered through a series of tanks.

The formation of the strip of sheets is of value in other treatments as well as the pickling process, and the operations of washing and drying can be carried on before the strip is sheared into sheets again.

In this invention I do not wish to cover the feature of the particular method of welding the-strips together, because I consider this an invention of itself, applicable to several steps of sheet treatment in the rolling .mill.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent, is v 1. A process of pickling metal, which con-' sists in feeding an elongated strip of con-.

tinuous nature' formed of said metal by means of a plurality of driven drums, said metal depending in a loop between the drums, said loop being arranged to pas s through a tank of pickle liquor.

2. A process of pickling metal, which consists in feeding an elongated .strip of continuous nature through a series of loops, said loops depending into a tank of pickle li uor.

3. A process of pickling sheet metal, w ich consists in joining sheets end to end in a continuous strip, and feeding said strip through a series of loops, said loops depending into a tank of pickle 1i uor.

.4. A process 0 v pickling sheet metal, which consists in joining sheets together end for end, and passing the continuous 'iece so formed through a series of baths 0 pickle liquor, and causing movement of the pickle liquor in a counter direction to the movement of the continuous piece through said baths. i 5. A process of pickling sheet metal,

which consists in joining sheets together end for end to form a continuous strip, and feedpickle liquor, through which pickle gliquor flows in a counter-direction to the of feed of the strips.

.JOHN TYTUS.

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